DS160PT801X16EVM Riser Card Evaluation Module
Abstract
The DS160PT801X16EVM is a 16-lane PCIe riser card board intended to be used for evaluation of the Texas Instruments DS160PT801 PCIe Gen4 retimer. The EVM uses the 1x16 Card Electromechanical (CEM) connector to enable quick system testing in a standard x16 socket and a standard PCIe endpoint. The evaluation board may be used with the SigCon Architect software program to provide register control and status information from the DS160PT801 devices. Contact a local Texas Instruments representative to obtain the SigCon Architect.
Figure 1-1 DS160PT801 EVMTrademarks
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1 EVM Control and Configuration Information
The DS160PT801X16 EVM uses an AT24C16 EEPROM to store retimer configuration settings. This EEPROM is pre-loaded with an EEPROM image with various settings to enable quick system bring-up for common-clock PCIe topologies.
Custom EEPROM images for compliance or separate reference independent spread (SRIS) clock topologies may be created and written to the EEPROM using the SigCon Architect software or by using the DS160PT801 I2C interface. For additional information on EEPROM programming through the I2C interface of the DS160PT801, please refer to the DS160PT801 EEPROM Programming Guide.(1)
Figure 1-1 DS160PT801X16EVM EEPROM
Control and ConnectionThe EE-PT801 connect headers (J21 and J24) allow for quick connection or disconnection of the EEPROM serial interface. Additional test access points are provided at header J23 to allow the user to monitor EEPROM activity. The J25 header may be used to Write Protect the EEPROM and prevent any changes to the current EEPROM image. When the EEPROM is disconnected, the retimer will completely rely on the pin-strap settings for configuration, which may be modified using the shunt jumpers included with the EVM.
1.1 Retimer Pin Controls
The DS160PT801X16EVM is pre-configured on power-up to use the retimer configuration stored in the onboard EEPROM. These settings may be adjusted by using the pin controls through the onboard headers and jumpers. There are 3 types of headers on the EVM for pin-controls: 2-level, 4-level, and 5-level headers. This section highlights the pin controls and how to adjust them. Additional information about pin settings is provided in the DS160PT801 data sheet.
Jumper options for 2-Level, 3-pin headers are as follows:
- No jumper on header pins – Input floating
- Shunt jumper at pins 1-2 – Input to 1.8 V or 3.3V
- Shunt jumper at pins 2-3 – Input to GND
Jumper options for 4-Level, 6-pin headers are as follows:
- No jumper on header pins – Input floating
- Shunt jumper at pins 1-2 – Inputs to 1.8 V
- Shunt jumper at pins 3-4 – Inputs 10 kΩ to GND
- Shunt jumper at pins 5-6 – Inputs to GND
Jumper options for 5-Level, 8-pin headers are as follows:
- No jumper on header pins – Input floating
- Shunt jumper at pins 1-2 – Inputs to 1.8 V
- Shunt jumper at pins 3-4 – Inputs 10 kΩ to 1.8 V
- Shunt jumper at pins 5-6 – Inputs 10 kΩ to GND
- Shunt jumper at pins 7-8 – Inputs to GND
| Header Designator | Jumper Position | Description |
|---|---|---|
| J1 | 1-2 | Disable CDCE6214 SSC clocking |
| J2 | 1-2 | Disable CDCE6214 clock output |
| J4 | 2-3 | Disable CDCE6214 EE_SEL |
| J6 | 7-8 | Set retimer U2 mode to dual-chip link-width manager |
| J7 | 5-6 | Set retimer U2 SMBus address to 0x20 |
| J8 | 5-6 | Set retimer U2 SMBus address to 0x20 |
| J11 | 5-6 | Set retimer U3 mode to dual-chip link-width follower |
| J12 | 3-4 | Set retimer U3 SMBus address to 0x22 |
| J13 | 5-6 | Set retimer U3 SMBus address to 0x22 |
| J16 | 2-3 | Assert CLKREQ#, 1 K pulldown to GND |
| J18 | 1-2 | Deassert Port 0 PRTRST#, 1 K pullup to 1.8 V |
| J20 | 1-2 | Deassert Port 1 PRTRST#, 1 K pullup to 1.8 V |
| J21 | 1-2 | Connect EE_CLK to retimer, enable EEPROM |
| J24 | 1-2 | Connect EE_DAT to retimer, enable EEPROM |
| J45 | 1-2 | Endpoint control of PRSNT#2 PCIe signal |
| J46 | 1-2 | Endpoint control of PRSNT#3 PCIe signal |
| J47 | 1-2 | Endpoint control of PRSNT#1 PCIe signal |
| J48 | 1-2 | Endpoint control of PRSNT#4 PCIe signal |
| J49 | 2-3 | Use clock source from CEM connector for REFCLK |
| J50 | 2-3 | Disable clock output from LMK00334 |
| J58 | 3-4 | Set voltage regulator to output 1.15 V |
| J59 | 1-2 | Enable U16 voltage regulator with 12 V supply |
1.2 USB-to-SMBus Interface
When using the default jumper configuration listed in Table 1-1, the DS160PT801 at location U2 is setup for SMBus address 0x20 (8-bit address). The DS160PT801 at location U3 is setup for SMBus address 0x22. The retimers can also be configured to other SMBus address combinations.
Figure 1-2 shows the locations of the SMBus address headers used to modify the default SMBus addresses for the retimers. For more information on valid SMBus addresses, please refer to the DS160PT801 data sheet.
Figure 1-2 DS160PT801X16EVM SMBus Interface Connections
To access the DS160PT801 devices through this interface, power must be applied through the SATA or Gold Finger connectors.
1.3 PCIe PRSNT# Signal Control and Configuration
The riser card allows users to alter the hot-plug presence detect signal (PRSNT#) returned to the PCIe host sytem. This is done by using the headers shown in Figure 1-3. By modifying the jumpers it is possible to have the PRSNT# signal represent a x1, x4, x8, or x16 mechanical link width. When using the default jumper configuration listed in Table 1-1, the DS160PT801 riser card allows the PRSNT# lines to be dynamically determined by the connected endpoint, which is useful for hot-plug detection.
Figure 1-3 DS160PT801X16EVM PCIe PRSNT# Controls
Removing the four shunt jumpers on J45–J48 and placing a single shunt across the lower two pins in one of the connectors allows the riser card to override PRSNT#. This is useful if a certain width is desirable. For example, by inserting a shunt jumper in position 2-3 on header J45 will force the PRSNT# status to represent a 1x4 mechanical link width.
